Yamanashi is very hot during summer because it is a basin surrounded by mountains. So it would be hard to walk around at this time of the year. But still, there are good things travelling in this season. You can see many flowers.
I posted a photo of the sunflower field in Akeno-cho a few days ago.
Information on Sunflower Festival
Duration: 21 Jul – 19 August
Address: 5664 Asao, Akeno-cho, Hokuto City, Yamanashi
Note: When you use a car navigation, it may be easier to find the place by putting the address of Yamanashi Flower Centre (2471 Asao, Akeno-cho, Hokut- City, Yamanashi) which is across the street from the sunflower field.
Access: The easiest way to visit the sunflower field is to use a car or take a taxi from Nirasaki Station of JR Chuo Line (about 20-min ride).
There are bus services from Nirasaki Station. It takes about 30 minutes.
Across the street from the sunflower field, there is Yamanashi Flower Center where I saw roses and hydrangea.
Shrines and temples have summer flowers, too. In Kai Zenko-ji Temple in Kofu City, I saw flowers of crape myrtle. They are usually red or white, but here I saw purple flowers.
The temple was constructed by Shingen Takeda, the feudal lord in this region in 1558
Information on Kai Zenko-ji Temple
Address: 36-1 3-chome, Zenko-ji, Kofu City, Yamanashi
Access: 12-min taxi ride from Kofu Station of JR Chuo-Line or 7-min walk from Zenko-ji Station of JR Minobu Line.
Yamanashi is also famous for its nature. Riverside walking is refreshing. Shoenkyo Gorge is one of the most popular hiking courses in Yamanashi Prefecture.
More Information on Shosenkyo Gorge
Address: Ikari-cho, Kofu City, Yamanashi
Access: The easiest way is to take a taxi from Kofu Station but please note that usually there is no taxi waiting in Shosenkyo area so on your way back you have to call a taxi.
The Shosenkyo Tourism Association provides the detailed information about access.
Another fun time in Yamanashi is fruits picking. During August, you can enjoy picking grapes and peaches. Katsunuma is famous for their grapes and wines. There are many wine chateaux in this area and you can taste not only fruits but also many kinds of wines, too.